RU226186U1 - Restriction device for measuring gas flow - Google Patents

Abstract

The utility model relates to diaphragm-type devices for measuring the flow and amount of gas in round pipelines. The claimed device includes a housing with holes for sampling gas pressure and a central hole for transporting gas equal to D. The housing is made with a groove in which a holder carrying a diaphragm with a calibrated hole is installed. The diaphragm is secured with a seal. The housing is closed with a lid to prevent gas leakage from above. The cover is fixed with a strip using spacer screws. The bar and the upper part of the body are made in the form of a dovetail connection. The housing has inlet and outlet pipes. The outlet pipe is made one-piece, with a length that is a multiple of at least four D from the vertical axis of the housing, while the central hole for transporting gas of the housing and the outlet pipe are bored out in one pass. The technical result of this solution is to increase the accuracy of gas flow measurement and increase the reliability of the device.

Description

The utility model relates to diaphragm-type devices for measuring the flow and amount of gas in round pipelines.

A narrowing device for measuring gas flow is known according to RF patent for utility model No. 48221, consisting of a housing with holes for gas sampling, with a holder with a diaphragm installed in it, equipped with inlet and outlet pipes, with flanges for connecting the housing to the gas pipeline. The outlet pipe is connected to the housing through a flange connection. The length of the outlet pipe is approximately equal to two diameters of the pipes themselves from the vertical axis of the housing.

Disadvantages of analogue:

the outlet pipe has a flange connection, in which a ledge can form, creating turbulence and gas turbulence in the pipeline, and distort gas flow readings;

the length of the outlet pipe, equal to approximately two diameters of the pipes themselves, is insufficient to stabilize the gas flow after narrowing the flow and contributes to vortex formation of the flow, which also reduces the accuracy of gas measurement;

the presence of a flange connection in the housing design reduces the reliability of the entire device due to possible gas leaks.

A device for measuring gas flow in pipelines is also known according to Russian Federation patent for utility model No. 84543, which refers to a diaphragm-type measuring complex for measuring the flow of gas transported through main and process pipelines in the oil and gas industry

The device consists of a housing with pressure sampling chambers separated by a diaphragm with a calibrated hole, an inlet pipe and an outlet pipe. The inlet pipe and the outlet pipe are equipped with flanges for connection to the gas pipeline and flanges for connecting to each other. In this case, the pressure sampling chamber is made collapsible using a flange connection, and the outlet pipe is made with a length approximately equal to two internal diameters of the pipe itself.

Disadvantages of analogue:

the outlet pipe is made of several assembly units connected to each other by flange connections. Assembly units processed separately from each other may differ in geometric dimensions. This solution, after assembly, creates ledges at the junction of the flanges and, accordingly, vortex formation and turbulence of the gas flow;

the presence of flange connections in the housing design reduces the reliability of the entire device due to possible gas leaks

The closest solution in technical essence - the prototype - is a quick-change narrowing device according to the RF patent for utility model No. 188537. The device has a housing with holes for sampling gas pressure and a central hole for transporting gas. The body is made with a through groove in which a holder carrying the diaphragm is installed. The housing has inlet and outlet pipes and connecting flanges. The outlet pipe is made with a connector in the form of a flange connection. The length of the outlet pipe from the vertical axis of the housing is a multiple of approximately two internal diameters of the central hole for gas transportation.

Prototype disadvantages:

the housing and the outlet pipe are two separate assembly units, made separately, which can differ in the roughness of the internal surface and geometric dimensions, which, when assembling these units, contributes to the appearance of ledges and joints, which in turn leads to a change in the distribution of gas flow velocity across the cross section of the central hole, promotes vortex formation of the gas flow and thus increases the error in measuring gas flow;

the length of the outlet pipe, a multiple of approximately two internal diameters of the central hole, is insufficient to stabilize the gas flow after narrowing the flow and distorts the gas pressure readings in the gas sampling hole, which also reduces the accuracy of gas measurement;

the presence of a connector in the outlet pipe reduces the reliability of the entire device due to possible gas leaks.

The purpose of the utility model is to create a constriction device for measuring gas flow, eliminating turbulence and turbulence of the gas flow in the area after the constriction of the flow and eliminating possible gas leaks through flange connections. The technical result of this solution is to increase the accuracy of gas flow measurement, in accordance with GOST 8.563.1-97 and increase the reliability of the device by eliminating flange connections

This task is achieved due to the fact that in a quick-change narrowing device for measuring gas flow, which contains a housing with holes for sampling gas pressure and a central hole for transporting gas with a diameter D, made with a groove in which a holder with a diaphragm is installed, sealing elements, the outlet pipe is made one-piece, with a length that is a multiple of at least four D from the vertical axis of the housing, and at the same time the central hole for transporting gas of the housing and the outlet pipe is bored in one pass.

The essence of the described utility model is illustrated by the following drawings.

In Fig. 1 shows a general view of the proposed device.

In Fig. 2 cross section of the proposed device A-A in Fig. 1.

A quick-change constricting device for measuring gas flow consists of a housing 1 with holes 2, 3 for sampling gas pressure and a central hole 4 for transporting gas equal to D. The housing 1 is made with a groove 5 in which a holder 6 is installed, carrying a diaphragm 7 with a calibrated hole d<D. The diaphragm 7 is fixed with a seal 8. From gas leakage from above, the housing 1 is closed with a lid 9. The cover 9 is fixed with a strap 10 using spacer screws 11. The strap 10 and the upper part of the housing 1 are made in the form of a dovetail connection. Housing 1 has an inlet pipe 12 and an outlet pipe 13 and connecting flanges 14. Housing 1, pipes 12 and 13 and connecting flanges 14 are made of a single all-welded structure, with a bored central hole of diameter D, without ledges and joints before and after the diaphragm 7, with a single roughness along the entire length of diameter D. In this case, the length of the outlet pipe from the vertical axis of the diaphragm 7 is at least 4D. The claimed device is connected to a section of the measuring pipeline, the geometric characteristics of which, as well as the placement of a restriction device, local resistances, and measuring instruments on it, are standardized by GOST 8.586.1-2005, 8.586.2-2005.

The device works as follows.

Through a quick-change constriction device for measuring gas flow, built into the measuring section of the pipeline and being part of this pipeline, gas is transported under pressure. Passing through the calibrated narrowing hole of the diaphragm 7, the gas flow narrows, which leads to a difference in gas pressure before and after the diaphragm. Gas pressure is taken through hole 2 in front of the diaphragm and hole 3 located after the diaphragm and is transmitted to differential pressure gauges and flow computers of the gas measuring station, which record the flow rate of the transported gas. If it is necessary to carry out maintenance or replace the seal 8 or diaphragm 7, they are removed from the housing 1 together with the holder 6. To do this, the spacer screws 11 are unscrewed from the threaded holes of the strip 10, and the cover 9 is dismantled. After maintenance or replacement of parts, all previous operations are performed in reverse order.

To ensure accuracy of pressure measurement in hole 3, it is important to ensure laminar gas flow in the outlet pipe, without turbulence, turbulence and twisting of the gas flow, because turbulence, turbulence and twisting of the gas flow distort the gas pressure readings in the gas sampling hole 3. To ensure laminar flow of gas at the gas outlet from the diaphragm, it is important to ensure the same geometry and roughness of the internal surface of the device after the diaphragm. For this purpose, the outlet pipe is made one-piece, without ledges, with a length that is a multiple of at least four internal diameters of the central hole D from the vertical axis of the body, and is bored in one pass together with the body. An outlet pipe length of more than 4D is necessary to stabilize the gas flow in the outlet pipe.

Thus, the proposed design of a quick-change orifice device makes it possible to increase the accuracy of gas flow measurement, in accordance with GOST 8.563.1-2005, and to increase the reliability of the device by eliminating possible gas leaks through the flange connection.

Claims (1)

A narrowing, quick-change device for measuring gas flow, containing a housing with holes for sampling gas pressure and a central hole for transporting gas with a diameter of D, made with a groove in which a holder with a diaphragm, sealing elements, an inlet pipe and an outlet pipe with an additional connector in the form of a flange are installed connections and connecting flanges for attaching the housing to the gas pipeline, characterized in that the outlet pipe is made one-piece, with a length that is a multiple of at least four D from the vertical axis of the housing, while the central hole for transporting gas of the housing and the outlet pipe is bored in one pass.